Results of treatment and long and short-term follow up of 13 patients (8 girls, 5 boys), aged 14-20 years (x:16.5) with prolactinomas, were assessed. Most frequent initial symptoms were: cephalea, puberty arrest or delay, galactorrhea and visual impairment. Pre-treatment evaluation showed variable and discordant responses of LH and FSH to LR-RH test, while results of TRH (TSH) test were normal in 8/9 patients (one girl had a primary hypothyroidism). Basal prolactin (PRL) levels were high in all patients (77 and 1150 ng/ml; mean +/- SD: 378 +/- 285), without further increase of TRH (mean: 25%). Eight patients had initially been operated; 7 remained hyperprolactinemic, requiring bromocriptine (BEC) after surgery. Five patients received BEC initially; CT scanning showed the absence of a substantial reduction of tumor size in 4 patients and there was no change in 1 girl. They all underwent surgery. Follow-up of 11 patients lasted between 2 and 12 years. Of those initially operated, 1 had a spontaneous return to normal gonadal function, and 5 patients required concomitant treatment. Of the 5 patients initially treated with BEC, 1 girl spontaneously resumed her cycles and became pregnant 10 months later, 1 girl completed her puberal development and at present she menstruates normally; 1 girl required concomitant progesterone treatment and the boy resumed his gonadal function. The secondarily operated girl remains normoprolactinemic, although without menstruation.(ABSTRACT TRUNCATED AT 250 WORDS)